Elastic yarn feeder for knitting machines



G. E. SINCLAIR Filed April 13. 1961 120 I x U I34 I32- I36 FIG. I.

ELASTIC YARN FEEDER FOR KNITTING MACHINES 5 Sheets-Sheet 1 INVENTOR. GEORGE E. SINCLAIR July 30, 1963 G. E. SINCLAIR 3,099,143

ELASTIC YARN FEEDER FOR KNITTING MACHINES 5 Sheets-Sheet 2 Filed April 15, 1961 INVENTOR. GEORGE E. SINCLAIR BY 1 i ATTO F IG. 2.-

July 30, 1963 GE. SINCLAIR 3,

ELASTIC YARN FEEDER FOR KNITTING MACHINES 5 Sheets-Sheet 3 Filed April 13, 1961 4 Mul INVENTOR. GEORGE E. SlNCLAlR ATTORN YS July 30, 1963 G. E. SINCLAIR ELASTIC YARN FEEDER FOR KNITTING MACHINES 5 Sheets-Sheet 4 Filed April 13, 1961 F I G. 4.

' -INVENTOR.

' GEORGE E. SINCLAIR Y u 7 ATTORi EYS July 30, 1963 Filed April 15, 1961 G. E. SINCLAIR ELASTIC YARN FEEDER FOR KNITTING MACHINES 5 Sheets-Sheet 5 FIG.7.

INVENTOR. GEORGE E. SINCLAIR ATTORNEYS United States Patent of Massachusetts Filed Apr. 13, 1961, Ser. No. 162,728

6 Claims.

This invention relates to elastic yarn feeders for knitting machines and has particular reference to a feeder for bare elastic yarns such as the synthetic elastomeric yarns known as spandex yarns. As will become clear, the invention is applicable to elastic yarns generally including those of natural and synthetic rubber.

Since their introduction spandex yarns have found particular application in the knitting of hosiery since they have an affinity for dyes and exceptional elasticity m ing them usable in the tops or cuffs of hosiery or in the leg or other portions thereof, wherein they are incorporated in various fashions by knitting, inlaying, interlacing or the like. In view of the high degree of elasticity and the fact that the yarn as used is desirably bare, feeding difficulties are encountered as compared with the heretofore used covered rubber. In particular, positive feed is desirable so that for a given progress of the knitting a definite length of the yarn in stretched condition is introduced into the fabric, which length may vary from point to point of the product. This is in contrast with the alternative procedure, used in connection with covered rubber, wherein feed at an established tension is provided. The spandex or similar bare yarn is actually fed under tension, but this tension is produced, not by tensioning means as such, but by virtue of the fact that the rate of feed with respect to the progress of production of the fabric is at a fixed rate of length as measured in untensioned condition (or at a given tension). The foregoing desired type of feeding creates some difiiculties when the yarn is automatically removed and introduced into the fabric. At the time removal occurs it is desirable, for proper clamping and cutting, that the tension, existing during feeding, should he suddenly relieved. Again, when the elastic yarn is reintroduced, its proper rate of feed should be rapidly assumed.

The general object of the present invention involves the attainment of the last mentioned conditions. In view of continuous high speed operation of the knitting machine rapid corrective actions are required, and these are achieved in accordance with the invention.

The foregoing general object and other objects relating to details of construction and operation will become apparent from the following description, read in conjunction with the accompanying drawings, in which:

FIGURE 1 is a plan view illustrating an elastic yarn feeding attachment in association with a knitting machine which is outlined only to the extent required for understanding of the invention;

FIGURE 2 is a vertical section taken on the plane indicated at 2-2 in FIGURE 1;

FIGURE 3 is a side elevation looking from the right hand side of FIGURE 1 showing the feeding attachment in its low speed feeding position such as is assumed during normal knitting;

FIGURE 4 is a view similar to FIGURE 3 but showing the attachment in the condition assumed during momentary high speed feed when tension on the elastic yarn is to be relieved;

FIGURE 5 is a fragmentary vertical section taken on the plane indicated at 5-5 in FlGURE 4;

FIGURE 6 is a fragmentary view showing certain controlling parts :as they would appear from the plane 6-6 in FIGURE 1; and

3,099,143 Patented July 30, 1963 "ice FIGURE 7 is a diagram illustrating certain electrical, pneumatic and mechanical connections involved in control.

Referring first to FIGURE 1, there is indicated by way of illustration at 2 a knitting machine of the conventional superposed cylinder type, this machine being illustrated primarily because it involves more elaborate procedures in introducing and removing an elastic yarn making particularly desirable the use of the present invention. Reference may be made particularly to the patent to Bentley et al. 1,838,651 for disclosure of this type of machine and particularly its yarn-handling operations. This machine is shown herein only in outline, since it is basically unchanged in carrying out the present invention, the circle of needles being indicated at 4, an elastic yarn feeding finger at s and the usual clamping and cutting means at 8. Reference to some of the other mechanisms of this machine will be made hereafter.

The bare elastic yarn is indicated at E, and approaches the mechanism at E being derived from a conventional cone or other package. in its approach to the yarn feeding finger it passes through a guiding eye 10, thence about the capstan-type feeder l2, and through guiding eyes 1 :and 16, the latter being carried by the feeding finger a.

The feeding capstan 12, which will be more fully described hereafter, is of the type illustrated and described in Lawson Patent 2,627,738, except that in accordance with the invention it is associated with special driving control means.

Power for operation of the feeding attachment is derived from a continuously rotating gear (not shown) of the knitting machine through the spur gears 18 and 2t) and bevel gears 22 and 24 which effect continuous rotation of a shaft 26 to which is secured a horizontal driving disc 23 which rotates counterclockwise as viewed in plan.

Engageable with the disc 28 is a rubber tire 3%) of a wheel 32 secured to a shaft 34- which is mounted in a bearing 1%. Secured to the housing of this bearing 36 by means of screws 4% there is a stationary gear 3% with which there mesh pinions 42 mounted on shafts 44 which have bearings in a carrier 46 which is carried by the shaft .34, being secured thereto by a set screw at 48. The shafts 44 respectively carry the horizontally projecting screws 50, the assembly of which constitute the capstan 12-.

The feed of the elastic yarn is effected at a desired rate of length thereof by the capstan in the fashion described in said Lawson patent. The elastic yarn E passes from the feeding eye It! a plurality of times about the screws and then through the eye 14. in starting up operation the elastic yarn may be rather arbitrarily placed about the screws, the number of turns about the screw assemblage being relatively immaterial so long as the yarn is wound several times thereabout. As feed proceeds a stabilized feeding distribution of the elastic yarn about and with respect to the screws is automatically achieved and feed takes place at a quite uniform rate with respect to the progress of the knitting. During the introduction of the elastic yarn, which may in any of the desired fashions indicated above, the rate of advance of the relatively untensioned yarn passing through the eye 10 is substantially lower than the linear rate of movement in passing through the feeding finger 6, the result being that the yarn is elongated to an extent depending upon the relative rates of movement of the capstan and the needles of the knitting machine. The normal feeding condition is as illustrated in FIGURE 3, with the tire 30 of the wheel 32 being at a relatively small radius from the axis of the disc 28.

Bearings 52 and 54 are provided in a bracket 56 which is secured to the machine frame. These bearings mount a rod 58 for both axially sliding movement and angular movement. Adjustably secured to the rod 58 is a lever 60, the hub 62 of which is secured to the red by means of a set screw 64. The bearing 36 forms part of a horizontally extending arm 66 of this lever 60, with the result that the assembly associated with shaft 34 will move axially with the axial movements of the rod 58 and angularly about the axis of this rod. The lever 60 is also provided with an upper portion 68 in which there is secured to extend laterally an elongated pin 70 engageable by a lever 72 pivoted to the frame at 74 and connected at its upper end to a Bowden wire 76 which is guided through a fixed bracket 78 which clamps its sheath. As will appear, when the Bowden wire 76 is pulled the lever 60 is rocked about the axis defined by the rod 58 to lift the bearing 36 and thereby lift the tire 30 away from contact with the disc 28.

A tension spring 80 secured at one end to a fixed bracket extension 82 and its other end to a hook 84 carried by the lever 60 urges the lever and its associated parts toward the left as viewed in FIGURE 3 to a position limited by engagement of a collar 86 with the portion of the bracket 56 providing the bearing 52. Engageable with the collar 86 is a downwardly extending arm of a bell crank 88 which is pivoted to the frame 9d and at 92 is engaged by the upper end of a Bowden wire 94 provided with a fixed guiding sheath 96. A downward pull on the Bowden wire will result in movement of the rod 58 to the right as viewed in FIGURE 4, resulting in positioning of the tire 30 at a greater radius from the center of the disc 28.

The conventional main pattern chain of the knitting machine is shown at 98, and in accordance with the invention is provided with one or more links having side lugs 100 engageable with a moving element of a switch 102 to close a circuit which is diagrammed in FIGURE 7. The switch is in series with the low voltage secondary of a transformer 184 which is continuously energized from the main power line 196. In series in the circuit is the solenoid 108 of an air valve 110 which is opened when the solenoid is energized to provide air from -a pressure supply line 112 to a cylinder 114- containing a piston rod 116 which is arranged to act on a lever 118 to exert a pull on the Bowden wire 94. Through the connections just described the Bowden wire is pulled when the switch 102 is closed by a lug 100.

The upper left-hand portion of FIGURE 1 and FIG- URE 6 show the portions 12% of the conventional yarn changing mechanism of the knitting machine which are involved in the operation of the feeding means herein. Slight modifications and additions are here involved. A lever 12'2 mounted on a fixed pivot at 124 is connected to the Bowden wire 76, previously described, and is provided with a pin 126 arranged to be lifted by cams 128 and 130 on a ring 132 which is adjustably mounted on a convention-a1 yarn finger control unit, as for example, by bolts passing through arcuate slots on the ring. The control unit, as more fully described in said Bently et al. patent comprises the yarn finger control cams 134, rack wheel 136, and clamp and cutter operating cams 138, this assembly being advanced as desired by the racking pawl 140 controlled in the usual fashion from the main chain 98.

The operation is as follows:

Let it be assumed, initially, that a rib top of a stocking is being knit by the superposed cylinder machine with the elastic yarn fed under conditions of uniform extension between or to the needles of the machine carried in the upper and lower cylinders thereof. Under these conditions both of the Bowden wires are released and as a consequence the existing conditions are those illustrated in FIGURE 3, the tire 39 now being in engagement with the driving disc 28 at a rleatively small radial distance from the center so that the feed is at a relatively low rate giving rise to the extension of the elastic yarn E. The rate of this feed is adjusted by setting the position of the arm 6% along the rod 58, the position of the rod being fixed by the engagement of the collar 86 with the end of the bracket 56.

When the elastic yarn is to be removed from action, chain 98 will advance lug 180 to close the switch 102, energizing the solenoid 188 and opening the valve to supply air to raise the piston 116, thereby rocking the lever 118 to exert a pull on the Bowden wire 94. This action rocks the bell crank 88 to shift the rod 58 and its associated parts to the position illustrated in FIGURE 4, locating the tire 38 at an increased radial distance from the center of the disc 28. The result is an immediate increase in rate of rotation of shaft 34 and a sudden increase in the rate of feed of the elastic yarn resulting in relief of tension therein in the portion between the capstan feeder and the yarn finger 6. As the chain 98 thus advances, the pawl 140 of the elastic yarn changer advances the rack wheel 136 to effect yarn removal in the usual fashion with attendant clamping and cutting of the elastic yarn, the end of which is located in the conventional clamp indicated at 8. Simultaneously the cam, for example 128, engages the pin 126 to rock lever 122 applying a pull on the Bowden wire 76 which rocks the lever 72 moving pin 70 to rock the lever 68 and thus disengage the tire 30 from the disc 23 to interrupt the feed of the elastic yarn.

The actions just described occur in rapid sequence, the increased rate of feed occurring for a short interval before the feed is interrupted. Thus, .there is the sudden relaxation of tension in the elastic yarn to permit the clamping and cutting to take place properly immediately thereafter followed by the complete cessation of feeding so that the elastic yarn is no longer pulled from its supply.

The sequential action results from the fact that the movement of the chain 98 which produces substantially immediate pull on Bowden Wire 94 initiates the racking action of pawl .149 on ratchet 136 with slight delay of movement of the latter to effect clamping and cutting of yarn E and termination of feed.

When the elastic yarn is reintroduced it is desirable that it should almost immediately be fed at the proper rate to provide its normal extension. This condition is achieved by the fact that as soon as the lug 1% passes, by advance of the pattern chain 98, beyond the switch 102, the solenoid 108 is deenergized and the supply of air from line 112 is cut off, bleeding of air at the valve 110 releasing it and the Bowden Wire 94 so that the rod 58 and its associated parts move to the normal position illustrated in FIGURE 3. However, the Bowden Wire 76 still remains in its pulled position so that the lever 72 maintains the tire 30 spaced from the disc 28. When reintroduction of the elastic yarn is to occur another step of advance of the pawl 140 takes place under the conventional controls and the elastic yarn is introduced to the needles in the usual fashion and released by the clamp. At the same time due to this advance of the mechanism the pin 126 drops off the cam 128 releasing the B'owden wire 76 so that the lever 60 under the action of gravity effects dropping of the tire 30 against the continuously rotating disc 28 with immediate resumption of the lower rate of elastic yarnfeed producing its desired extension.

Usually, in conventional fashion, a few needles are arranged to seize and knit the leading end of the elastic yarn as it is introduced to anchor it against creeping. The same expedient is desirably used when the yarn is withdrawn, the trailing end of the elastic yarn being then knit by a few needles for a similar purpose.

While the rod 58 is shown as occupying a fixed axial position determined by collar 86 during knitting, it will be evident that it may be controlled variably by the pattern mechanism so that during knitting the extension of the elastic yarn E may be varied either continuously or in steps to provide fashioning or shaping of the product being made.

It will be evident that various changes may be made in details of the invention without departing from the scope thereof as defined in the following claims.

What is claimed is:

'1. In combination with a knitting machine having needles, means for feeding an elastic yarn to the needles, :means for moving said feeding means to insert and withdraw said elastic yarn, and clamping and cutting means for the elastic yarn; a feeder of positive feeding type for supplying yarn at predetermined feed rate to said feeding means and needles during activity of the feeding means and means for increasing the yarn supplying rate of said feeder at the time \of withdrawal of said elastic yarn, thereby to decrease the tension of the portion of the yarn between the feeder and said elastic yarn feeding means.

2. In combination w'th a knitting machine having needles, means for feeding an elastic yarn to the needles, means for moving said feeding means to insert and withdraw said el-astic yarn, and clamping and cutting means for the elastic yarn; a feeder of positive feeding type for supplying yarn at predetermined feed rate to said feeding means and needles during activity of the feeding means, means for increasing the yarn supplying rate of said feeder at the time of withdrawal of said elastic yarn, thereby to decrease the tension of the portion of the yarn between the feeder and said elastic yarn feeding means, and means for interrupting the supply of said elastic yarn by said feeder following the increase of yarn supply rate.

3. In combination with a knitting machine having needles, means for feeding an elastic yarn to the needles, means for moving said feeding means to insert and withdraw said elastic yarn, and clamping and cutting means for the elastic yarn; a feeder of positive feeding type for supplying yarn at predetermined feed rate to said feeding means and needles during activity of the feeding means, means for increasing the yarn supplying rate of said feeder at the time of withdrawal of said elastic yarn, thereby to decrease the tension of the portion of the yarn between the feeder and said elastic yarn feeding means, means for interrupting the supply of said elastic yarn by said feeder following the increase of yarn supply rate, and means for restoring said feeder to condition for lower rate of supply of said elastic yarn during the time of interruption of the supply of said elastic yarn.

4. In combination with a knitting machine having needles, means for feeding an elastic yarn to the needles,

means for moving said feeding means to insert and withdraw said elastic yarn, and clamping and cutting means for the elastic yarn; a feeder of positive feeding capstan type for supplying yarn at predetermined feed rate to said feeding means and needles during activity of the feeding means and means for increasing the yarn supplying rate of said feeder at the time of withdrawal of said elastic yarn, thereby to decrease the tension of the portion of the yarn between the feeder and said elastic yarn feeding means.

5. In combination with a knitting machine having needles, means for feeding an elastic yarn to the needles, means for moving said feeding means to insert and withdraw said elastic yarn, and clamping and cutting means for the elastic yarn; a feeder of positive feeding capstan type for supplying yarn at predetermined feed rate to said feeding means and needles during activity of the feeding means, means for increasing the yarn supplying rate of said feeder rat the time of withdrawal of said elastic yarn,

thereby to decrease the tension of the portion of the yarn between the feeder and said elastic yarn feeding means, and means for interrupting the supply of said elastic yarn by said feeder following the increase of yarn supply rate.

6. In combination with a knitting machine having needles, means for feeding an elastic yarn to the needles, means for moving said feeding means to insert and withdraw said elastic yarn; and clamping and cutting means for the elastic yarn, a feeder of positive feeding capstan type for supplying yarn at predetermined feed rate to said feeding means and needles during activity of the feeding means, means for increasing the yarn supplying rate of said feeder at the time of Withdrawal of said elastic yarn, thereby to decrease the tension of the portion of the yarn between the feeder and said elastic yarn feeding means, means for interrupting the supply of said elastic yarn by said feeder following the increase of yarn supply rate, and means for restoring said feeder to condition for lower rate of supply of said elastic yarn during the time of interruption of the supply of said elastic yarn.

References Cited in the file of this patent UNITED STATES PATENTS 1,600,464 Foster Sept. 21, 1926 1,606,756 Filberg Nov. 16, 1926 2,053,877 Plumb Sept. 8, 1936 2,087,820 Sheppard July 20, 1937 2,110,088 Lawson Mar. 1, 1938 

1. IN COMBINATION WITH A KNITTING MACHINE HAVING NEEDLES, MEANS FOR FEEDING AN ELASTIC YARN TO THE NEEDLES, MEANS FOR MOVING SAID FEEDING MEANS TO INSERT AND WITHDRAW SAID ELASTIC YARN, AND CLAMPING AND CUTTING MEANS FOR THE ELASTIC YARN; A FEEDER OF POSITIVE FEEDING TYPE FOR SUPPLYING YARN AT PREDETERMINED FEED RATE TO SAID FEEDING MEANS AND NEEDLES DURING ACTIVITY OF THE FEEDING MEANS AND MEANS FOR INCREASING THE YARN SUPPLING RATE OF SAID FEEDER AT THE TIME OF WITHDRAWAL OF SAID ELASTIC YARN, THEREBY TO DECREASE THE TENSION OF THE PORTION OF THE YARN BETWEEN THE FEEDER AND SAID ELASTIC YARN FEEDING MEANS. 